How to Retrieve Data in the TextBox Based on ComboBox in VB.Net and MS Access Database

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Now, in this tutorial, I’m going to teach you how to retrieve data in the textbox based on combobox in VB.Net and MS Access Database. This method has the ability to display all the data in a certain textbox by selecting the data in the combobox. If you this function the output will be displayed in all 5 textboxes.

Creating an Application

Step 1

Open Microsoft Visual Studio 2015 and create a new windows form application.
Step 2

Do the form just like shown below.

Step 3

Press F7 to open the code editor. In the code editor, add a namespace for OLeDB

to access OLeDB

libraries.

1. imports System.Data.OleDb;
   

Step 4

Create a connection between the access database and vb.net. After that, declare all the classes that are needed.

1. 
   
2. Dim
   
   con As
   
   OleDbConnection = New
   
   OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source="
   
   & Application.StartupPath & "\dbproducts.accdb"
   
   )
   
3. Dim
   
   cmd As
   
   OleDbCommand
   
4. Dim
   
   da As
   
   OleDbDataAdapter
   
5. Dim
   
   dt As
   
   DataTable
   
6. Dim
   
   sql As
   
   String
   
7. Dim
   
   maxrow As
   
   Integer
   

Step 5

Create a method for filling data in the combobox.

1. 
   
2. Private
   
   Sub
   
   load_cbo(sql As
   
   String
   
   , cbo As
   
   ComboBox)
   
3. Try
   
4. con.Open
   
   ()
   
5. cmd = New
   
   OleDb.OleDbCommand
   
6. da = New
   
   OleDb.OleDbDataAdapter
   
7. dt = New
   
   DataTable
   
8. 
   
9. With
   
   cmd
   
10. .Connection = con
    
11. .CommandText = sql
    
12. 
    
13. End
    
    With
    
14. da.SelectCommand = cmd
    
15. da.Fill(dt)
    
16. 
    
17. cbo.DataSource = dt
    
18. cbo.DisplayMember = "Product"
    
19. cbo.ValueMember = "ProductID"
    
20. 
    
21. 
    
22. 
    
23. Catch ex As
    
    Exception
    
24. MsgBox(ex.Message)
    
25. 
    
26. Finally
    
27. con.Close
    
    ()
    
28. da.Dispose()
    
29. End
    
    Try
    
30. End
    
    Sub
    
31. 
    

Step 6

Create a function for getting the total number of rows in the database.

1. 
   
2. Private
   
   Function
   
   get_maxrow(sql)
   
3. Try
   
4. con.Open
   
   ()
   
5. cmd = New
   
   OleDb.OleDbCommand
   
6. da = New
   
   OleDb.OleDbDataAdapter
   
7. dt = New
   
   DataTable
   
8. 
   
9. With
   
   cmd
   
10. .Connection = con
    
11. .CommandText = sql
    
12. 
    
13. End
    
    With
    
14. da.SelectCommand = cmd
    
15. da.Fill(dt)
    
16. 
    
17. maxrow = dt.Rows.Count
    
18. 
    
19. Catch ex As
    
    Exception
    
20. MsgBox(ex.Message)
    
21. 
    
22. Finally
    
23. con.Close
    
    ()
    
24. da.Dispose()
    
25. End
    
    Try
    
26. Return maxrow
    
27. End
    
    Function
    

Step 7

Write the following code for filling the data in the combobox in the first load of the form.

1. 
   
2. Private
   
   Sub
   
   Form1_Load(sender As
   
   Object
   
   , e As
   
   EventArgs) Handles MyBase.Load
   
3. sql = "Select * From tblproducts"
   
4. load_cbo(sql, cboProduct)
   
5. End
   
   Sub
   

Step 8

Write the following code for retrieving the data in the textbox when the button is clicked.

1. 
   
2. Private
   
   Sub
   
   btnFind_Click(sender As
   
   Object
   
   , e As
   
   EventArgs) Handles btnFind.Click
   
3. sql = "Select * From tblproducts Where ProductID = "
   
   & cboProduct.SelectedValue & ""
   
4. maxrow = get_maxrow(sql)
   
5. If
   
   maxrow > 0 Then
   
6. With
   
   dt.Rows(0)
   
7. txtProductID.Text = .Item("ProductID"
   
   )
   
8. txtProductName.Text = .Item("Product"
   
   )
   
9. txtDescription.Text = .Item("Description"
   
   )
   
10. txtPrice.Text = .Item("Price"
    
    )
    
11. txtCategory.Text = .Item("Category"
    
    )
    
12. End
    
    With
    
13. End
    
    If
    
14. End
    
    Sub
    

Download the complete source code and run it on your computer.
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